Process of concentrating and maturing viscose.



L. NAUDIN. v PROCESS OF GONGENTEATING AND MATUBING VISGOSE.

APPLIMTION FILED una, 1907.

986,306, V Patented Mar.7,1911.

BPBUIIBNS.

` dated August 4, 1902. Another 15 to 18 C; In Y cordance with 'either of the processes above the viscose, the

Y ing to the lattertreatment,` the viscoseundergoes a slow and prolonged treatment in aV LAURENT NAUnIN,'or rms,-

' Y vrscosn, or' PARIS, FRANCE,

FRANCE, AssrGNon. ro SOCIT rnANArsn nn LA A CORPORATION OIE FRANCE.

rnocnss or coNcnNzrnnrrNe AND mrtrnrNG viscosa.

986,306, Y Speciication of Application ined Aprn 5, i907. serial No. 366,634.

To all'whom it may concern: y

Be it known that I, LAURENT NAUDEN,

citizen of the French Repu lic, residing at Paris, Department 'of the Seine, France, have invented certain new and useful Improvements in Processes of Concentratin Y and MaturingViscose, owhich the following is a specilication.

This invention relates to a process of malr-A ing viscose, and it has for its object to provide an improved process that insures a product that isA comparatively rich iu celluloseand possesses elastic and plastic properties so that the viscose may be used to better advantage the manufacture of Elms, such as those used in photography and for other purposes, also as dressings or coatings for various materials,` and is also capable of being used to better advantage than ordinary viscose in paper manufacture, the product when derived in the form of a thread or film being also useful for various purposes."

In-the spinning industry, and also in lilm manufacture, to obtain the best results in the `worlng of latter should have reached a certain state of maturity, that is to say, the

spontaneous reaction, or otherwise, a certain degree of density. Severalprocesses oftreating viscose toobtain sucharesult,havebeen proposed, one othese processes involving a heating of viscose to a temperature Vvarying between 70 and 90 C., together with the application of an alkali, such a rocess being described in French- Patent o. 323,473, treatment proposed is described in French Patent 330,753, dated March 31, 1903, and accordtank at a relatively low temperature, say 'of treating the viscose in acdescribed, a considerable loss occurs Vby rea;-v Son of the large percentage of, lay-products' resulting therefrom, such as carbonate, sulfo-ca'rbonate, etc. Another process that has been -proposed consists in heating the viscose until the xanthate is coagulated in the presence of carbonated and sulureted by-products, the material being next washed to eliminate the icy-products, and is thentreated with an alkaline solutii'rto conden'se or 5 it has beenfo'und that in order Letters Patent. Patented Mal'.

(Specimens.)

the most favorable conditions, is that only a small percentage of cellulose, the essential factor or constituentin the practical application of viscose, is retained, and for the viscose have been According cose relatively ing elastic and plastic properties is obtained by evaporating the water which is the solvent, by the application of heat to the-mass ata relatively low temperature and while the material is in 'vacuo a boiling of the material being thereby obtained at a temperature of say 32 to 35 C., the mass being kept in a constant state of agitation, and the quantities lof water evaporated being controlled properly-at each this manner a viscose is 'obtainable that is much richer in cellulose; and, moreover, the chemical factors aremore nearly in equinecessarily limited.

the reference to the saline by-products, and the molecular state of the xanth'ate which does complete formula being represented by CMH',OmOCStSNai` v f Experience hasshown that xanthate of cellulose in aqueous solution, under the influence of' a suiiiciently high` temperature,

. passes through different states of molecular condensation in which states the carbon suc- Above the valu'eC38 the mass is coagulated vand it cannot be used for practical purposes. Practice demonstrates that the viscose -1S most stable when the carbon is of approximately the value-C18. Below this value, that is to say, when the carbon is expressed by the term C6 or C12, the molecule does not possess Solidity, and the resulting products in those cases would be devoid of resistance. Hence, 'viscose may be worked to the best advantage in spinning and other industries when t e carbon has a value of between C18 and C24.

' 'The composition of the viscose as matured by the process Aof my invention is variable to a considerable extent, it depending vupon the proportions of the reacting elements such as alkali, cellulose, carbon disuld and water. The proportion should be determined according to the intended use of the cellulose reconstitute the viscose. But' the, objieolo11-l Y for, in some cases, it would .not be a disad- 7, ieri.,A

to such process, even when operated under.

reason above stated, the practical uses of llbriumregarding the amount of c'elluiose,`

proportion of non-combined soda, with not exceed the molecularV size C18, theY cessively has the'values C6, C12, C18, C24, G36.

to mypresent invention, avisrich 1n cellulose and possess-l operation, and in vantage to used-a large `excess of free soda,

` While injother cases, the-v presence of an 'exmymature viscose may be given as follows: -Pure cellulose..l 14. 00 Caustic soda r Y 8.00 `Carbonated soda `1.30. Sulfid, polysuld, andhyposulfite-of' soda 1 1.00

cess ofisoda must be prevented.

An exam le of an average composition of wat.. igiiiiii'f."22:21:; 75.70 'I I 100.00

AFifteen percent.' of cellulose may be considered as the .maximum Above this percentage, the mass even without coagula` .4 tion, -1s so thick that concentration becomes impossible at the low temperature involved in the present process. 'A viscose possessing greater stabilitymay be obtained without altering the proportion ofgcellulose by aug-v menting the amount of free caustic soda. For

. The'accompanying drawing illustrates an n. apparatus thatis capable of being used in more Scrapers B carried arms B"sec ure d to an o erating shaft 1, the. Scrapers bein y preferab y arranged so as t'o* shaft 1 is journaled lat its'lower end' in ay bearing 2 Aarranged within the tank, and its upper end extends through a stuiing'box 3 v an performing the process, in accordance with the present invention, the mixingtank and the condensing apparatus beingshown in= section;-

This a paratus comprises; a tank; A of suitable orm, to receive the mass for treatment, the tank being surrounded by a jacket adapted to receive a fluid that serves to heat or refri erate the contents of the tank. The

mass wlthin the tank is agltated by oneor operate on al portions ofthe tank. The

is provided with a gear wheel4 which cooperates with a corresponding gear Wheel mounted on 'a suitable driving, shaft 6.

-, Thieitop C through which the mass to be treated maf:r

through a discharge of the'tank is provided with van inlet be intro uced into the tank, and the mass is Withdrawn from the Atank after treatment the inlet and outlet being vprovided with means; for closing them in order that a vacuum or pressure may maintained within 'the tank. The vapo1 through the pipe E an .tained in them is y the respective uct vwill be hig y through the freed from the mass is withdrawn through a discharge pipe E which leads to a condensing coil F, the latter; being'mountedgin a condensing tank G ada 4ted to contain/water or the like for cooling the coil F, the cooling `coil discharging into aseparate chamber G in the lower portion of the tank and the latter may be maintained ata vacuum pressure by means of a vacuum pump of any suitable'- kind, that is to be connected to the nipple I'.

The condensed `vapor may be withdrawn from the chamber Gr by'mea'ns o f thedrip pipe H.

viscose is preferablyl filtered and is then in,-

According to the presentinvention, the 8 troduced into'the tank through the opening C, and a vacuum is maintained within the tank by exhausting air from the chamber G and from the cooling coil F' and the discharge pipe E, the mass being at the'sanie time heated to.

Lmass during the distillation" and I.tov prevent local overheatin of anyportion of the mass. By reason of t e vacuum the tank, the viscose bo .at a relatively low temperature, or` at the. temperature a 'temperature preferably ranging .between .32 and C. .The ,mo-v tion of the'scrapers' B serves to agitate the'- pressure within 1 above mentioned, and the air and gaseous sulfureted by-products are liberated from the mass together with .the water from the same which is freed in the form of steam or vapor, these products l being withdrawn conde ed'in the cooling being. finally withdrawn through -the opening I, and the liquid or condensationcollects 1n the chamber G. By heating the mass to the temperature above described while n vacuo and during agltation, the material is simultaneously concentratedv and matured, the treatment being coil F, the gases maintained for a eriod determined accordstate of concentration, a

ing to the desire twot hours bemg `usually period'of one or sufficient.

If the mass is maintained "in vacuo during the-'entire treatment, a very `large percentage of water contained in the viscose,l escapes 1n the'form of va or, and in thisca'se the prod- Vconcentrated, and the vis-y cose will be very rich in cellulose. On the other hand, should the communication between the tank and the vacuum pump be cut olf. after the vair and sulfureted lay-products have been extracted' from the mass, the vrscose willmature without concentration, .be'- I cause 'of the interruption ,of evaporation.' l

-The"viscose, after the treatment has'` been '5' is' withdrawn from the tank discharge pipe G, and tl1'e`trea a.t ment'may be repeated with a fresh mass of material.

In the manufacture ofv cellulose, it srst.. A transformed into alkali cellulose and; there.

completed,`

after sulfureted. The xanthate thus pro-I' duced is dissolved in a suitable Aquantity of sodium liydroxid. .The percentage of cellulose in tlie viscose so'formed does notexceed ten per cent. Moreover, the prolonged agilal ion of the mass in the presence of air converts. the uniss into a thick emulsion. While in that eouditiointlie substance is not suitable for tlie. preparation of films. 'According to tbe presentinvention, however, viscose at teu per cent. or less is boiled'at a low temperature and ifa. vacuo. as hereinbeused, and in iuanni'aeturing films, the viscose isspread or laid upon websor papei's and converted in tlie. usual manner into the films.-

llie sullnraiion of cellulose ;is effected willi au excess ol carbon disulfid, and dnrin tlie polyinerizalion. carbon disuld' is free Walei; and carbon disulfid are found in the condenser. '.l`lie preseneeof carbon disulfid in tliedistilled vapors occurs if the refrigeration is very eil'eeiive, otherwise carbon disullid, tlie boiling point of which is rela tively' low, escapes to the atmosphere llu'ougli tbe' vacuiun puu'ip which Works continuously during tlic concentration.

Viscose obtained in accordance witlithev process above described, contains a relativel high percentage of cellulose that enables 1t to be used to' greater advantage 'in Various maturing thereof. y In testimony whereof I have hereunto set industries, and the equilibrium between its component constituents insures a product 1n the form of a tlireador film whiclrpos- VSesses a high degree of elasticity and plastieity. l

I claim as my invention- 1. A process of treating vlscose consisting in simultaneously heating and agitating viscose solution 'whilewi vacuo' of a degreeff' sufiicient. to cause boiling ofthe mass at a relatively low temperature, and maintaining the inass under treatment n 'vacuo and at the said temperature toreniove tlic water 4evaporated from tlie mass' to .etlect conccnftrat'i'on and maturing tliereoi 2. A process of treating Viscose consisting in heating and agitating4 a viscose solution z'zi vacuo of a degree suflicient to cause distilla- -tion of the water in the mass at a relatively lowv temperature, maintaining tlie mass n vacuo, thereby withdrawing tbe water evaporated from tlie niass until the desired concentration vis efl'ected, and allowing tlie teniperatnre to descend to normal temperature.

3. A i-iroeess of treating viscose. which consists in subjecting auvscose solution to agitation z'n 4vacuo andwliile heated to a teniperat'ure ranging between 32 and 35'? C. to effect distillation of the watercontai'ned iii the mass, and maintaining tlie mass in 'vacuo and substantially at sucli temperature for a period suiiiciei'it to ell'ect concentration and my hand in presence of two subscribing witnesses.

' LAURENT AUDIN;

Witnesses EMILE KLo'rz, GEORGES LEDAY. 

